Leaf type micro switch



Oct 1953 H. HUBBELL LEAF TYPE MICRO SWITCH Filed May 4, 1950 Patented Oct. 27, 1953 UNITED STATES ATENT OFFICE LEAF TYPE MICRO SWITCH Harvey Hubbell, Long Hill, Conn. Application May 4, 1950, Serial No. 159,976 Claims. (Cl. 200-457) This invention relates to micro switches such as are employed to obtain a quick make and break of an electric circuit upon relatively slight movement of the switch elements. Certain forms of switches of this type have a spring strip the flexing of which in one direction or the other causes a movable contact or contacts to snap back and forth to make or break an electric circu1 An object of this invention is to provide a micro switch of simplified form and improved operation.

A further object is to provide an improved micro switch in which the spring strip assembly is constructed and arranged to provide within itself substantially all movable operating parts of the switch.

A further object is to provide an improved micro switch constructed and arranged to permit the operating parts of the switch to be easily and quickly assembled and disassembled in a supportin casing.

A further object is to provide a micro switch having an improved construction of spring strip in which the operating means forms an integral part.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In this drawing:

Fig. 1 is a plan view of a micro switch constructed in accordance with one embodiment of the invention;

Fig. 2 is a longitudinal section on the line 2--2 of Fig. l with the parts in closed circuit position;

Fig. 3 is a similar view with the parts in open circuit position;

Fig. 4 is an end elevation looking from the right of Figs. 1 and 2, and

Fig. 5 is a cross section on the line 5-5 of Fig. 1.

The particular embodiment of the invention which has been chosen for the purposes of illustration includes a casing H of insulating material such, for example, as a natural or synthetic rubber or plastic composition, having a base l2, vertical side walls l3, and one end wall 14, the opposite end of the illustrated casing bem; p n- As shown, a pair ,of stationary electrio contacts I5 are mounted on spaced current conducting plates l6 secured to the top of the end wall [4 by screw members I! or the like, and adapted to be connected in any suitable manner to an associated electric circuit. These screws may also be the binding screws for connecting the electric conductor wires to the members l6. An insulating lug or shoulder l8 on the end wall It separates the current conducting plates IS.

The operating mechanism is illustrated as comprising a metallic spring strip 2| formed with spaced side arms '22 connected at one end by a current conducting cross arm or contact plate 23 supporting a pair of contact buttons 24 for movement into and out of engagement with the stationary contacts I5 to make and break the associated electric circuit. As illustrated, the movable buttons 24 are mounted on a supporting current-conducting plate 25 which is in turn fastened to the cross arm or contact plate 23 by rivets 26 or the like, but if preferred the contacts 24 may be mounted directly on the end portion 23 of member 2|. At its other end the strip is provided with an operating cross arm 2'! connecting the side arms '22.

A centrally positioned divided tongue 3|, having one section 32 connected to the contact-supporting cross arm 23 and a second or operating section 33 connected to the operating cross arm 2'! at the other end of the side arms 22, extends between and parallel to the side arms 22. These sections 32 and 33 could be considered as separate tongues extending in opposite directions toward each other from end portions 23 and 21. The inner separated ends of the tongue sections 32, 33 have inwardly extending lugs 34 with side shoulders 34a centering and holding the respective ends of a compression spring 35 which is compressed between the tongue sections 32, 33 and a handle 36 extends outwardly from the operating cross arm 21 in position to be operated by hand, or by a thermostatic control member, or any other suitable operating means.

The spring strip 21 is firmly connected to the casing H to permit flexing of the tongue sections 32, 33.

As illustrated, the spring strip 2! has fiat supporting lugs 38 extending outwardly from each side arm 22 and engageable in lug receiving slots or recesses 39 in the side walls l3 of the casing H at the open end thereof, see Fig. 4, permitting the spring strip 2| and assembled movable contacts 24 and compression spring 35 to be easily and quickly assembled and disassembled with the casing H merely by sliding the supporting lugs 38 into or out of the slots 39 in which they are frictionally retained. The supporting lugs 38 are positioned on the side arms 22 substantially opposite the free end of the operating tongue section 33, so that the hereinafter described fiexing of the spring strip 2| occurs about an axis passing through the lugs 38 and adjacent the inner end of the tongue 33.

In operation, a relatively slight movement of the handle 3% transversely to the plane of the spring strip 2| snaps the movable contacts 24 into and out of engagement with contacts I5 and therefore to and from the contact engaging circuit closing position shown in Fig. 2. Each movement of the handle 3t causes the cross arm 23 and the movable contact buttons 24 to move with a snap action in the opposite direction to that of the handle 35. For example, as the hanle as is moved upwardly from the position shown in Fig. 2 to that shown in Fig. 3, the portion of the side arms 22 adjacent the handle and the operating cross arm ".2? are flexed upwardly about the supporting lugs 33 as a hinge point. This causes the inner end of the operating tongue section connected to the handle end of the strip to be flexed downwardly toward the posi tion of Fig. 3. This shifts the compression spring 35 into the position shown in Fig. 3 and snaps the tongue section 32 connected to the movable contacts 2d upwardly into the position shown in Fig. 3, flexing the inner end portions of the arms 22 downwardly and causing the movable contact buttons M to shift downwardly and break the circuit with a quick snap action. When the handle 35 is pressed downwardly in the opposite direction, the side arms 22 adjacent the handle 36 are flexeddownwardly around the lugs 38, raising the inner end of tongue section 33 and shifting the compression spring into the position shown in Fig. 2, thus snapping the tongue section 32 into the position shown and snapping the movable contacts 24 upwardly into circuit closing position to complete the circuit. It will thus be seen the movement of the end portion carrying the contacts 24 is in the opposite direction to that of operating handle 36 in each case. A stop such, for example, as a pin 40, may be provided to limit movement toward the open position or away from contacts l5.

The spring strip 2i and movable contacts 24 are easily removed from the casing by pulling on the handle 36 to withdraw the supporting lugs 35 from the slots 38, and can be as easily as sembled by a reverse operation.

Although I have described a specific embodiment of micro switch in detail, the invention can be variously modified and adapted within the scope of the appended claims.

Having thus set forth the nature of my invention, I claim:

1. A microswitch element comprising a flexible spring strip having a pair of spaced flexible side arms, a contact plate including a cross member connecting the side arms at one end of said strip, an operating cross member connecting the other ends of said arms, a handle connected to said operating cross member, a divided tongue extending parallel to and located between said side and having separated opposed flexible sections, one section connected to said contact plate and extending therefrom toward the operating cross member and the other section forming an operating section connected to said other cross member and extending therefrom toward the first cross member, both tongue sec tions being movable through the strip from one side to the other, a spring compressed between the inner ends of said tongue sections, and supporting means for said side arms at points acljacent the free end of the operating tongue section, whereby pressing said handle in one direction flexes the adjacent part of said strip about said supporting means to thereby shift the operating tongue section from one side of the strip to the other and cause said spring to flex said other tongue section in the opposite direction and shift it through the strip to the opposite side from the operating tongue section to shift said contact plate in the direction opposite to the movement of said handle.

2. A micro switch element comprising a flexible spring strip having a pair of spaced flexible side arms, a contact plate including a cross member connecting the side arms at one end of said strip, an operating cross member connecting the other ends of said arms, a handle connected to said operating cross member, a divided tongue extending parallel to and located between said side arms comprising two sections having separated free ends each movable through the strip from one side to the other, one section connected to said contact plate and the other section forming an operating section connected to said other cross member, a spring compressed between the inner ends of said tongue sections, and means including lugs extending. outwardly from said arms for supporting said side arms at points adjacent the free end of the operating tongue section, whereby pressing said handle in one direction flexes the adjacent part of said strip about said supporting means to thereby shift said operating tongue section from one side of the strip to the other and cause said spring to flex said other tongue section in the opposite direction and shift it through the strip to the opposite side from the operating tongue section to shift said contact plate in the direction opposite to the movement of said handle.

3. A micro switch comprising a casing, electric contacts mounted therein, a flexible spring strip having a pair of spaced flexible side arms connected together at opposite ends by cross members, one cross member comprising a contact plate at one end of said strip adapted to bridge said contacts, a handle connected to the cross member at the other end of said strip and projecting outwardly of said casing, a divided tongue extending parallel to and located between said side arms and comprising two sections having separated free ends each movable through the strip from one side to the other, one connected to said contact plate cross member and the other forming an operating section connected to said other cross member and extending in opposite directions, a helical spring compressed between the inner ends of said tongue sections, and means for removably supporting said side arms on said casing to permit said strip being withdrawn from said casing by said handle including inwardly opening slots in opposite side walls of the casing and an outwardly extending ear on each of said side arms engaged in said slots in said casing.

4. A micro switch element comprising a flex.- ible spring strip having a pair of spaced flexible side arms, a contact plate including a cross member connecting the side arms at one end of said strip, an operating cross member connecting the other ends of said arms, a handle cone nected to said operating cross member, a divided tongue extending parallel to and located between said side arms comprising two sections extending in opposite directions and having opposed separated inner free ends each movable through the strip from one side thereof to the other, one section connected to said contact plate and the other section forming an operating section connected to said other cross member, a spring compressed between the inner ends of said tongue sections, and supporting means for said side arms at points adjacent the free end of the operating tongue section, whereby pressing said handle in one direction flexes the adjacent part of said strip about said supporting means to thereby shift the operating tongue section from one side of the strip to the other and cause said spring to flex said other tongue section in the opposite direction and shift it to the other side of the strip from the operating section to shift said v contact plate in the direction opposite to the movement of said handle, said supporting means including outwardly extending lugs on said side arms positioned adjacent the free end of said operating tongue section. I

5. A micro switch comprising a casing, electric contacts mounted therein, a flexible spring strip having a pair of spaced flexible side arms con nected together at opposite ends by cross members forming a contact plate at one end of said strip, a handle connected to the cross member at the other end of said strip, a divided tongue extending parallel to and located between said side arms comprising a pair of separate flexible sections extending in opposite directions and having opposed inner free ends each movable through the strip from one side thereof to the other, one section connected to said contact plate and the other to said other cross member, a helical spring compressed between the inner ends of said tongue sections, and means for supporting said side arms on said casing at points adjacent the free end of the tongue section connected to said other cross member.

' HARVEY HUBBELL.

References Cited in the file of this patent UNITED STATES PATENTS 

